This invention relates to an electric brake system for a cargo trailer and specifically to a power source for powering an electric brake system for a cargo trailer.
Typically, heavy trucks include a truck and a cargo trailer. The truck includes an internal combustion engine that drives an alternator to generate electricity. Electric brakes mounted to the tractor are powered directly by electricity generated from the alternator. Typically, a single electric brake requires approximately 20 to 30 amperes of current during heavy stop conditions in order to have enough power to slow or stop the heavy truck. Wire sizes for transmitting electrical energy between the power source for the truck and the electric brake are sized to reduce line drop so the brake will have required voltage and current for the brake motor. There are restrictions on the size of wire used between the truck and trailer for transmitting electrical power to the electric brakes. Further, the electrical connection between the truck and trailer is a predetermined standard size wire and connector.
The size of the wire and the standard connector cannot be adjusted and is the limiting factor for current supplied to the electric brakes in the non-powered trailer. As appreciated an electric brake on each wheel of the cargo trailer requires approximately 20 to 30 amperes of current in order to apply sufficient braking force during a hard stop condition. The current required for all the wheels of the cargo trailer is between 360 and 440 amperes when the brakes are fully applied for a hard stop. Current losses caused by line drop through the standard sized wire and connector are such that during hard stop braking conditions the amount of available current may be insufficient to actuate the electric brakes.
Accordingly, it is desirable to provide a system for powering electric brakes mounted to the cargo trailer independent of power generated by the towing vehicle to minimize the limitations caused by the electrical connection between the truck and trailer.